Study Finds Differing Long-Term Effects of Hand-Held Cellphone Laws

ARLINGTON, Va., Oct. 16 /PRNewswire-USNewswire/ -- Phoning while driving and texting behind the wheel are in the news. This is the highway safety issue of the moment, the subject of cartoons and, on a more serious side, the focus of legislation. A key question is whether such laws succeed in changing patterns of driver cellphone use.

Insurance Institute for Highway Safety researchers recently conducted a new round of observations of driver use of hand-held phones in 3 jurisdictions where the practice is banned. The findings, along with results of previous studies, reveal differing effects. In the District of Columbia, the

proportion of drivers using hand-held phones dropped by about half immediately after a ban took effect in 2004. Nearly 5 years later use has edged up a little, but the decline is largely holding relative to nearby Virginia and Maryland.

The story is different in New York, the first US state to prohibit drivers from using hand-held phones in 2001. Connecticut enacted a ban in 2005. Comparing trends in these states over time, researchers found immediate effects of both laws. Cellphone use declined an estimated 76 percent in Connecticut and 47 percent in New York. But then use began going back up.

Effects of the laws over time: To quantify the long-term effects, researchers observed phone use multiple times during 2001-09 in both the study states and nearby communities without phone bans. The purpose was to estimate the proportion of drivers expected to be using hand-held phones if the laws hadn't been enacted. By this measure, hand-held phone use was an estimated 65 percent lower in Connecticut, 24 percent lower in New York, and 43 lower in the District of Columbia than would have been expected without the laws.

In Connecticut and New York, phone use was higher in spring 2009 among women of all ages compared with men and higher among drivers younger than 25 versus 25-59 year-olds. Only 1 percent of drivers 60 and older were observed using phones.

"What's clear from the surveys, despite some variability in their findings, is that bans on hand-held phoning while driving can have big and long-term effects, but the safety implications still aren't clear," says Institute president Adrian Lund. "Many drivers still use their hand-held phones, even where it's banned, and other drivers simply switch to hands-free phones, which doesn't help because crash risk is about the same, regardless of phone type."

Phone use, texting, and crash risk: The question of the risk associated with using various electronic devices while driving was the focus of debate at a recent summit convened by Ray LaHood, US Secretary of Transportation. Participants cited a number of studies.

For example, 2006 research from the Virginia Tech Transportation Institute involved instrumenting cars with video and sensors to estimate the risk associated with phoning. The main finding is an almost 3-fold increase in the odds of crashing or nearly crashing when dialing a hand-held phone. The increase is 1.3 for talking. However, this study included only 100 cars and not many crashes occurred during the study period, so the results are inconclusive.

Researchers at the same organization say the risk associated with text messaging may be much higher, based on a new study of truck drivers. The main finding is a 23-fold increase in the odds of crashing, nearly crashing, or drifting from a travel lane among truckers who texted while they drove. A limitation is that most of the incidents involved lane drift or other driver error, not crashes, and it's unknown how such incidents relate to actual crashes.

Two studies that rely on the cellphone records of crash-involved drivers show big increases in crash risk when drivers talk on phones, whether hands-free or hand-held. The risk of a crash involving injury or property damage is 4 times as high.

Other studies have been conducted on simulators. Virtually all of these confirm that phoning impairs driving performance, and the impairment is similar for hand-held and hands-free phones.

"Whether the risk associated with phoning or texting while driving is 4-fold or 23-fold or somewhere in between, the fact of the risk is clear," Lund points out. "Manual dialing and texting seem especially risky, but talking also involves crash risk, and drivers spend more time talking on phones than dialing."

Besides the precise risk associated with hand-held phone use, there's more researchers don't know. Banning hand-held phones does reduce their use while driving, for example, but it isn't known whether such bans also reduce crashes. Nor is it known how drivers respond when hand-held phones are banned. This has important implications concerning the laws state legislators are considering.

Laws may be difficult to enforce: The crash risk is about the same, whether drivers use hand-held or hands-free phones, so if motorists respond to hand-held bans by switching the type of phone they use, they may not be reducing crash risk. What they're doing, though, is engaging in a practice that's harder to curb because laws against it are harder to enforce.

"Police officers can see whether a driver is holding a phone to the ear, but it's going to be much harder to determine if a driver is sending a text message or talking on a hands-free phone," Lund points out.

No US state currently bans all drivers from using hands-free phones. Twenty-one states and the District of Columbia prohibit beginning drivers from using any type of phone, including hands-free, but these laws are hard to enforce. This was the finding in North Carolina, where teenage drivers didn't curtail phone use in response to such a ban, in part because they didn't think the law was being enforced.

Technology could make a difference: The best approach would be to use technology to control how and when motorists use their cellphones. Devices are in the works that would block phone use in moving vehicles, but a problem is that such devices would block phoning by passengers as well as drivers. To get around this, some systems include a passenger mode, but it's unclear whether drivers can be prevented from activating it to circumvent the whole purpose of the devices.

The main use of such technology may be among fleet managers to control phone use by employees or among parents who want to monitor their teenage drivers. However, phone blockers of any sort aren't yet in widespread use, and their effects aren't known.